Does Arsenic Contamination Affect DNA Methylation Patterns in a Wild Bird Population? An Experimental Approach

Abstract

<p>Pollutants, such as toxic metals, negatively influence organismal health and<br>performance, even leading to population collapses. Studies in model organisms have shown that<br>epigenetic marks, such as DNA methylation, can be modulated by various environmental factors,<br>including pollutants, influencing gene expression, and various organismal traits. Yet experimental<br>data on the effects of pollution on DNA methylation from wild animal populations are largely<br>lacking. We here experimentally investigated for the first time the effects of early-life exposure to<br>environmentally relevant levels of a key pollutant, arsenic (As), on genome-wide DNA methylation<br>in a wild bird population. We experimentally exposed nestlings of great tits (Parus major) to arsenic<br>during their postnatal developmental period (3 to 14 days post-hatching) and compared their<br>erythrocyte DNA methylation levels to those of respective controls. In contrast to predictions, we<br>found no overall hypomethylation in the arsenic group. We found evidence for loci to be<br>differentially methylated between the treatment groups, but for five CpG sites only. Three of the<br>sites were located in gene bodies of zinc finger and BTB domain containing 47 (ZBTB47), HIVEP<br>zinc finger 3 (HIVEP3), and insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1). Further studies are needed to evaluate whether epigenetic dysregulation is a commonly observed phenomenon in polluted populations and what are the consequences for organism functioning and for population dynamics.<br></p><p><br>KEYWORDS: pollution, Parus major, environmental epigenetics, ecological epigenetics, ecotoxicology<br></p>